Steel-furnace



A..FISHERJ I STEEL FURNACE. APPLICATION FILED FEB. 24, I920.

1,389,346. Patented Aug. 30,1921.

2 SHEETS-SHEET I.

by I

A. FISHER. sun wan/we. APPLICATION Hub FEB, 24, 1920. 1 89,346, Patented Aug. 30, 1921,

2 SHEETS-SHEET 2.

ALFRED FISHER, or CHICAGO, ILL-mom.

STEEL-FURNACE. 7

7 Specification of Letters Patent- Patented Aug. 30,

,Application filed February 24, 1920. Serial No. 360,679.

'to an improved type ofa melting furnace wherein the fire-brick lining has the fire-pot constructed with the side walls vertical starting on a level with the lower end of the furnace crucible and extending upwardly a slight distance above the upperend of said crucible, from which point the fire-brick wallsconverg'e toward the top of the furnace thereby affording a fire-pot adapted to produce a very high temperature for melting steel. I

It is an object of this invention to provide a melting furnace wherein the fire-p0t is soshaped that a very high temperature may be reached for the purpose of melting steel.

Another object of the invention is to provide a furnace wherein a temperature of approximately a thousand degrees higher can be reachedthan that obtainable in brass furnaces, thereby producing a furnace adapted for melting steel.

It is furthermore an object of the invention to providea melting furnace wherein the fire-pot is so shaped that the blast-flames directed into the fire-pot are choked in the upper end of the fire-pot for the purpose of concentrating said blast-fiames around the furnace crucible to evenly reduce a charge of steel therein.

It is an important object of this invention to provide an improved type of steelfurnace wherein the combustion'chamber is of substantially cylindrical form' for about the height of the furnace crucible, said cylindrical portionjoining a conical upper chamber section and a smoothly rounded grooved lower chamber section.

Other and further important objects of this invention will be apparent from the disclosures in the accompanying drawings and specification. c

The invention (in a preferred form), is

illustrated in the drawings and hereinafter more fully described.

' On the drawings: V Figure 1 'is an elevation of a'steel furnace embodying the principles of this invention.

Fig. 2 is a top plan view thereof.

Fig. 3 is a vertical section taken on'line 3-3, of Fig.2; 1

Fig. 4 is a transverse section taken on line 4-4,ofFig.'1. r i Fig. 5 is an enlargedlongitudinal section taken through one of the blast-burners.

As shown on the drawings: I

The furnace proper comprises a supporting or base plate 1, supported by legs 2. Mounted upon the base platel, is a metal furnace caslng or shell 3, adapted'to be removably closed by means of a lid 4, provided with a counterweight .5, and with a latch device 6.

The metal casing 3, is provided witha fire-brick lining, the various elements of which are so constructed to afford a fire-pot or combustion chamber adapted to produce very eflicient resultswhereby a temperature of approximately four thousand degrees Fahrenheit may be obtained for melting steel in the furnace crucible. The furnace lining may be constructed of lire-clay, firebrick or any other suitable highly material, and said lining embraces a firebrick floor or bottom layer 7, provided with a rounded annular channel or groove 8, which at one side of the furnace opens into a lower or slag chamber 9, for receiving'slag or molten metal shoulda crucible break in the furnace. Asshown the slag chamber 9, is formed by extending the base plate 1, downwardly onone side to a. distance below the bottom of the main portion of the furnace and providing therefor a removable dumping door 10, having a fire-brick lining 11. The frontof the slag chamber 9, is closedby means of a removable shutter or refractory door. 12, having an outlet opening-18,.therein to permit the molten metal or slag to flow therethrough. As shown in Fig. 3, the

groove. 8, forms a boss or pedestal 14, within the furnace for the purpose of receivinga crucible 15. Mounted upon the .fii'eebriclr floor 7, area plurality of-fire-brick rings 16, disposed one above the other and extending upwardly toa short distance above the top of the crucible 15. Each of the fire-brick rings or elements 16, is provided with a cylindrical central opening '17, the walls of which are vertical and afford a straight chamber section the lower end of which connects with the rounded groove 8. Supported on the upper fire-brick ring 16, is an upper layer of fire-brick 18, provided with an upwardly tapering or conical choke chamber or opening 19, the diameter of the lower or widest portion of which is the same as the diameter of the openings 17 in the lire-brick rings 16.

Projecting through the metallic casing 8,

and through passages oropenings 20, in the,

lower fire-brick ring 16, are two inwardly and downwardly inclined blast-burners which are substantially tangential with re spect to the walls of the combustion cham her or fire-pot for the purpose of directing the blast-flames downwardly into the annular groove 8, of the fire-pot, to cause said blast-flames to flow spirally around the crucible 15. Each blast-burner embraces a tapered twyer 21, having a fuel pipeor tube 22, axially disposed therein 'and controlled by a needle valve 23. Connected with the needle valve 23, is an oil or hydro carbon feed pipe 2 Air under pressure is supplied to each blast-burner through a plug valve 25, which is connected with an air blast pipe 26, having a control valve 27, therein. The air blast pipe 26,.may be connected with any suitable type of'blower. Each blast-burner is provided with an a'ir exhaust pipe 28, to permit the escape of the air when the plug valve 25, is turned to prevent air from entering the blast-burner twyer 21. v

The operation is as follows:

By releasing the latch 6, the lid or cover l, may be opened to permit a charge of steel to be placed within the crucible 15. The blast-burners are ignited and the lid is locked in closed position by the latch 6. The amount of oil or hydrocarbon, and the air entering the blast-burners is adapted to be regulated by adj ustment of the air valve 27, the needle valves 23, and the plug valves 25. The blast-flames entering the furnace fire-pot, are directed tangentiall and downwardly into the fire-pot bottom groove 8, and striking the fire-pot walls flow centrifugally around the crucible 15.

- Should a crucible be broken the molten or partly molten metal may be removed from the furnace slag chamber 9 by removing the bottom or dumping door 10, or by opening the front door '12. If the metal or slag is in a thoroughly molten condition, it may be drawn off through the outlet opening 13.

The peculiar design of the furnace combustion chamber or fire-pot is the important feature of this invention. In ordinary melting furnaces of the type herein described a maximum temperature of approximately three thousand degrees Fahrenheit is obtainable, which is suflicient for melting brass, bronze and similar metals, but is not suiiicient for melting steel. By the use of a fire-pot shaped as described and shown, a maximum temperature of approximately four thousand degrees is obtainable, thus permitting the improved type of furnace to be used for melting steel. The intense degree of heat is obtained by directing the blast-flames from theblast-burners tangen tially into the fire-pot groove 8, from which position the flames flow centrifugally up- 7 wardly in the cylinderchamberl'i, around the crucible to evenlyhea't all parts of the same and thereby cause an even reduction of the charge contained within the crucible. The walls ofthe chamber 17, are vertical and extend upwardly from the top of the pedestal 14, ton point a short distance above the top of the crucible. The upper end of the fire-pot comprises a choking chamber 19, which is of conical shape so that the inclined walls forming the same act to choke or concentrate the centrifugal blast-flames in the lower section of the firepot around the crucible, This arrangement permits a high temperature to reached sufiicient to melt steel, which cannot be'done' in similar types of furnaces having fire-pots of shapes different from that shown in" Fig. 3.

I am aware that numerous details of c onstruction' may be varied through awide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted 100 otherwise than necessitated by the prior art;

I claim as my invention:

1. In a furnace 'of-the class described a combustion chamber floor having a concave annular bottom groove affording a crucible support," a cylindrical intermediate combu's tion' chamber portion having vertical walls extending from the top of the cruciblesupport to a point sligl'ltly above the upper end of a crucible placed on said support, and a conical umaer section above the cylindrical portion adapted to choke the blast-fiames and concentrate the same in said cylindrical portion of the combustion chamber around the crucible. V

2. In a furnace of theclass described a firepot embracing a floor having a'roun'ded annular groove,va cylindrical intermediate section of a heigl'it approximately equal to that of the furnace crucible, and an up wardly converging upper fireepot section for choking the blast-flames, and retaining the same in saidcylindrical section around: the crucible. I v

3. A furnace casing fire-brick liningcomprising a lire-brick floor having a rounded annular groove therein forming a pedestal for receiving a crucible, a cylindrical intermediate fire-brick section on said flo'o'r' hav- 7 ingvertical inner Walls extending from the top of the pedestal upwardly above the upper end of the furnace crucible, and an upper fire-brick section on said cylindrical section provided with an inner upwardly converging conical wall for. choking the blastdrical section around the crucible.

4. Afurnace fire-pot having a cylindrical intermediate portion joining a conical upper portion and a grooved lower portion.

5. A steel furnace comprising a supporting frame, a casing supported thereon, a cover for said casing, and a fire-brick lining for said casing comprising a fire-brick floor having a rounded annular groove therein overlapping a slag chamber also formed in a said floor, an intermediate fire-brick section on said floor having a cylindrical chamber therein with vertical'walls which join said groove, and an upper fire-brick section on said intermediate section, said upper section having a conical chamber the greatest diameter of which is equal to the diameter of said cylindrical chamber.

I 6. A steel furnace comprising a supporting said casing, blast-burners projecting into sald casing, and a fire-brick lining for said casing comprising a floor having a rounded flames and keeping the same 1n said cyl1n-;

annular groove therein forming a crucible pedestal for supporting a crucible, said floor having a slag chamber therein communicating with said groove, an intermediate lining section on said floor having a cylindrical chamber therein with vertical walls which join the outer peripheral edge of said groove, and an upper lining section on said intermediate section, said upper section having a conical chamber which diverges downwardly tojoin the upper end of said cylindrical chamber at a point above the upper end of the furnace crucible.

In testimony whereof I have hereunto subscribed my name in the presence of a subscribing witness.

' ALFRED FISHER. Witness:

FRED E. PAESLER. 

